Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.mrao.cam.ac.uk/ppeuc/hep/ward/ward.ps Äàòà èçìåíåíèÿ: Mon May 12 20:52:12 1997 Äàòà èíäåêñèðîâàíèÿ: Tue Oct 2 09:45:30 2012 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: jet

Results from LEP and SLD
David Ward
University of Cambridge
ffl W Physics at LEP II
W mass
Triple Gauge Couplings
ffl Other SM physics at LEP II
Two­fermion, QCD
ffl Searches for new physics at LEP II
Higgs, 4­jet, etc.
ffl A few highlights from LEP I
Mainly electroweak
Apologies ­ many interesting areas, especially from LEP I, SLD,
not covered owing to lack of time; e.g. b physics, Ü physics,
two­photon, QCD.
D.R. Ward PPEUC 9 April 1997

Data from LEP
ffl 1989­1995
LEP I )¸ 160 pb \Gamma1 (¸ 5 \Delta 10 6 visible Z 0 decays) /
experiment
ffl November 1995
LEP 1.5 -- 130­136 GeV )¸ 5 pb \Gamma1 / experiment
ffl July/August 1996
LEP II -- 161 GeV )¸ 10 pb \Gamma1 / experiment
ffl October/November 1996
LEP II -- 172 GeV )¸ 10 pb \Gamma1 / experiment
And in the future:
ffl 1997
¸184 GeV )¸ 100 pb \Gamma1 / experiment ?
ffl 1998/9
¸192 GeV )¸ 300 pb \Gamma1 / experiment ?
Data from SLC
ffl Up to 1996, ¸ 5 pb \Gamma1 , with P e up to 80%.
D.R. Ward PPEUC 9 April 1997

W + W \Gamma production at LEPII
Basic mechanisms:
W ­
W +
e ­
e +
Z
W ­
W +
e ­
e +
g
W ­
W +
e ­
e +
n
Principal aims:
ffl W mass
Indirect measurements from LEP I give MW to about
\Sigma40 MeV.
Hence aim is to match this precision by direct measurement
-- test SM, constrain Higgs mass etc.
ffl Triple Gauge Couplings
Search for any anomalies in the WWZ and WWfl couplings.
Need to select the following channels:
W + W \Gamma ! qqqq (¸ 46%)
W + W \Gamma ! qq`š ` (¸ 44%)
W + W \Gamma ! `š ` `š ` (¸ 10%)
D.R. Ward PPEUC 9 April 1997

W + W \Gamma ! qqqq
DALI_D7 ECM=161 Pch=128. Efl=158. Ewi=56.2 Eha=60.6 RQ_41437
Nch=33 EV1=0 EV2=0 EV3=0 ThT=0 96-07-11 13:30 Detb= E1FFFF
Run=41437 Evt=5974
ALEPH
2 Gev EC
8 Gev HC
FISH-EYE VIEW
2 Gev EC
8 Gev HC
x
-
x
-
x
x
-
-
-
x
- x
x
x
x
x
-
-
- xx
-
-
x
x
- -
-
-
-
-
x
-
o
o
o
o
o o
o
o o o
o
o
o
o o
o
o o
o
o
o
o
o
o
o
o
o
o
J1
J1
J1
J2
J2
J2
J3
J3
J3
J4 J4
J4
J1 + J2 = 82.0 GeV/c
J3 + J4 = 75.8 GeV/c
2
2
ffl High multiplicity
ffl High visible energy
ffl Momentum balance
ffl Four (or more) jets
ffl Significant background from Z/fl events (¸ 25%), good
efficiency (¸ 80% at 172 GeV).
Also combinatorial b/g (3 jet pairings per event)
D.R. Ward PPEUC 9 April 1997

W + W \Gamma ! qq`š `
ffl Isolated, high momentum lepton
ffl Missing momentum
ffl Two (or more) jets
ffl Low background (¸ 5%), high efficiency (¸ 85%) for e/¯;
(Ü less clean).
D.R. Ward PPEUC 9 April 1997

W + W \Gamma ! ` \Gamma š `
` + š `
Y
X
Z
ffl Two isolated leptons
ffl High momentum
ffl Acoplanar (i.e. missing p T )
ffl Low background (¸ 5 \Gamma 10%), reasonable efficiency
(¸ 70%).
D.R. Ward PPEUC 9 April 1997

W Mass at threshold
At 161 GeV, just above W + W \Gamma threshold, the W + W \Gamma
cross­section is very sensitive to MW .
Rs [GeV]
s
WW
[pb] LEP Average
W + W - cross section at LEP
0
2
4
6
8
10
12
14
16
155 160 165 170 175 180
m W (GeV)
W
+
W
-
cross
section
(pb)
LEP Average
s WW = 3.69 ± 0.45 pb
m W = 80.40 +0.22 GeV
m W = 80.40 -0.21 GeV
Rs = 161.33 ± 0.05 GeV
-
m W from s WW at 161 GeV
0
1
2
3
4
5
6
7
79 79.5 80 80.5 81 81.5 82
MW measurements from the four LEP experiments are in
excellent agreement. The errors are predominantly statistical.
(¸ 30 events / experiment ) \DeltaM W to ¸ 0:3%).
LEP 161 GeV W mass
ALEPH 80.14 +0.35 GeV
80.14 -0.35
DELPHI 80.40 +0.45 GeV
80.40 -0.45
L3 80.80 +0.48 GeV
80.80 -0.42
OPAL 80.40 +0.45 GeV
80.40 -0.42
LEP 80.40 ± 0.22 GeV
common 0.07 GeV
m W [GeV]
79.5 80 80.5 81 81.5
D.R. Ward PPEUC 9 April 1997

W Mass by direct reconstruction
At higher energies, MW is obtained by direct reconstruction of
jet­jet invariant masses. Kinematic fit techniques are used to
improve resolution.
A typical mass spectrum Compare all experiments
0
5
10
15
20
25
40 45 50 55 60 65 70 75 80 85 90
m / GeV
Events
/
GeV
OPAL preliminary
Rs = 172 GeV
LEP W mass 172 GeV
ALEPH 80.59 ± 0.35 GeV
DELPHI 79.95 ± 0.39 GeV
L3 80.72 ± 0.35 GeV
OPAL 80.16 ± 0.35 GeV
LEP 80.37 ± 0.19 GeV
common 0.06 GeV
c 2 /dof = 2.9/3
m W [GeV]
80 81
At present, errors predominantly statistical.
Statistical power of direct reconstruction technique comparable
to threshold method; systematics largely independent.
D.R. Ward PPEUC 9 April 1997

W Mass by direct reconstruction
qqqq channel potentially more problematical than qq`š --
more background
and colour reconnection + Bose­Einstein -- estimated to
contribute ¸ 50 MeV error to combined result.
Important to try to measure such effects in data,
e.g. comparing qqqq with qq`š.
qqqq MW =80.28\Sigma0.21 GeV
qq`š ` MW =80.48\Sigma0.22 GeV
Recent study shows no evidence yet for BEC between different
W bosons.
D.R. Ward PPEUC 9 April 1997

W Mass -- world compilation
W­Boson Mass [GeV]
m W [GeV]
c 2 /DoF: 0.0 / 1
80.0 80.2 80.4 80.6 80.8
pp­colliders 80.37 ± 0.10
LEP2 80.38 ± 0.14
Average(world) 80.37 ± 0.08
LEP1/SLD 80.323 ± 0.042
State: m97
If LEP delivers 100 pb \Gamma1 /experiment in 1997, the LEP error
should reduce to about 0.06 GeV.
D.R. Ward PPEUC 9 April 1997

Triple gauge couplings
ffl One of the important goals of LEPII is to test the SM
predictions of ZW + W \Gamma and flW + W \Gamma couplings.
ffl Need 2 \Theta 7 parameters to describe most general Lorentz
invariant WWV vertices.
ffl C, P, gauge invariance reduces to 5
– fl ; – Z (=0 in SM) Ÿ fl ; Ÿ Z ; g Z
1 (=1 in SM)
ffl LEP I precision data constrains possible anomalous
couplings. Focus on three combinations which are not
strongly constrained:
\DeltaŸ fl \Gamma \Deltag Z
1 cos 2 ` W = ff BOE
\Deltag Z
1 cos 2 ` W = ff W OE
– fl = ff W
All zero according to the Standard Model.
ffl Anomalous couplings generally increase the W + W \Gamma
cross­section, change the angular distribution of produced
W bosons, and affect their helicity states (! different decay
angular distributions).
D.R. Ward PPEUC 9 April 1997

Triple gauge couplings
An example of the W \Gamma polar angle distribution
(only W + W \Gamma ! qq`š ` used so far, since this gives W charge
unambiguously).
­0.14 +0.26
­0.25 ALEPH
+0.36 +0.49
­0.43 DELPHI
­0.01 +0.42
­0.36 L3
­0.07 +0.34
­0.30 OPAL
a Wf
g
WWZ
=0.
­1 ­0.5 0 0.5 1 1.5
Average:
ff W OE ! 0:4 at 95% c.l.
If there were no WWZ
coupling, g Z
1 = 0,
ff W OE = \Gamma0:95
clearly excluded.
D.R. Ward PPEUC 9 April 1997

Single W production
Many possible diagrams contribute to the Weš final state, e.g.:
f
f _
e ­
e ­
e +
g
n _
W
W
Typically electron along beam pipe, so signatures are a single
energetic lepton, or two acoplanar jets with missing E T .
L3 Run # 660201 Event
#5876 O
O O O
O
O O
O
O
O O O
O
O O
O
O
O O O
O
O O
O
x
y
z
This event from L3 has a 40 GeV electron.
D.R. Ward PPEUC 9 April 1997

Single W production
ffl L3 observe signals in both leptonic and hadronic channels
oe(Weš) = 0:61 +0:43
\Gamma0:33 \Sigma 0:05 pb
(at 172 GeV). c.f. SM ! 0.35 pb.
ffl Sensitive to TGC, especially WWfl, and hence
complementary to W + W \Gamma .
L3
63% CL
95% CL
SM prediction
GRC4F
l g
Dk
g
­6
­4
­2
0
2
4
6
­6 ­4 ­2 0 2 4 6
D.R. Ward PPEUC 9 April 1997

Two­fermion production
ffl Initial state radia­
tion is very important, especially radiative return to the Z pole:
µ +
µ ­
e ­
e +
(Z/g) *
Non­radiative
µ +
µ ­
e ­
e +
Z 0
g
Radiative return
ffl Main interest is in the non­radiative sample, where new
physics could show up.
ffl Define s 0 as the effective mass 2 of the ff system after ISR.
electrons
muons
taus
hadrons
Energy (GeV)
Cross
Section
(nb)
10 ­4
10 ­3
10
­2
10 ­1
1
10
10 2
60 80 100 120 140 160 180
Energy (GeV)
Cross
Section
(nb)
10
20
30
40
88 89 90 91 92 93 94 95
0
0.2
0.4
0.6
0.8
1
50 100 150
Rs /GeV
Asymmetry
OPAL
preliminary
(a) e + e ­
Rs /GeV
Asymmetry
combined µ + µ ­ ,t + t ­
OPAL
(b)
preliminary
­1
­0.5
0
0.5
1
50 100 150
D.R. Ward PPEUC 9 April 1997

Two­fermion production
ffl In electroweak fits at the Z peak, fl­Z interference is not
well constrained by the data -- often fixed to SM expectation
ffl Above the Z peak, fl­Z interference important, so data can
be used to constrain it
ffl e.g. in the S­matrix formalism, j tot
had parametrizes the fl­Z
interference in the hadronic cross­section.
­1.0
­0.5
0.0
0.5
1.0
91.17 91.18 91.19 91.2
m Z [GeV]
j
tot had
L3
68% CL
Z Data only
all Data
SM
D.R. Ward PPEUC 9 April 1997

Two­fermion production
Place limits on new physics, e.g.
ffl Four­fermion contact interaction (general parametrization for
new effects). Many possibilities (lepton/hadron, V, A, L, R
couplings). Typical limits on energy scale \Lambda ? 2 TeV (more
stringent than LEP I)
ffl Contribution of a virtual exchanged scalar (leptoquark?,
RPV squark?) on e + e \Gamma ! qq
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
100 150 200 250 300 350 400
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
100 150 200 250 300 350 400
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
100 150 200 250 300 350 400
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
100 150 200 250 300 350 400
H1 all flavors
b depleted
M (GeV/c 2 )
l
up­type coupling
OPAL
preliminary
(a)
H1
all flavors
b depleted
b­tag
M (GeV/c 2 )
l
down­type coupling
OPAL
preliminary
(b)
D.R. Ward PPEUC 9 April 1997

QCD at LEP II
Main interest so far is evolution of QCD observables with energy
scale.
Use non­radiative events, and remove W + W \Gamma background.
e.g. Running of ff s (c.f. ff s (M Z )=0.118) .
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0 25 50 75 100 125 150 175 200
Q (GeV)
a
s
(Q)
NLO NNLO Lattice
OPAL
ALEPH
DELPHI
L3
Deep Inelastic Scattering
e + e ­ Annihilation
Hadron Collisions
Heavy Quarkonia
ep ® jets
91 GeV 133 GeV 161 GeV
172 GeV
ff s (172 GeV)
ALEPH 0.108\Sigma0.008
DELPHI 0.104\Sigma0.014
L3 0.105\Sigma0.009
OPAL 0.093\Sigma0.008
D.R. Ward PPEUC 9 April 1997

QCD at LEP II
Another example -- running of average multiplicity.
NLLA QCD prediction:
hn ch i = Aff b
s exp [a=
p
ff s ]
0
5
10
15
20
25
20 40 60 80 100 120 140 160 180 200
E cm /GeV
ch
>
l OPAL
ALEPH
s DELPHI
L3
t MARK II
AMY
n TASSO
TPC
HRS
M JADE
NLLA QCD fit
JETSET
hn ch i(172 GeV)
ALEPH 26.3\Sigma0.6
DELPHI 27.4\Sigma1.0
L3 27.2\Sigma0.8
OPAL 25.9\Sigma1.0
D.R. Ward PPEUC 9 April 1997

The Higgs Boson
Essential that LEP II reaches highest Higgs masses, to match
LHC.
Z
H
e ­
e +
Z *
e ­
e +
e ­
e +
H
Z
n e
n ­
e
e ­
e +
H
W
Main production mechanism is ZH. Hence, principal possible
search channels are:
HZ ! b.r. Comment
bbqq 60% need b­tagging; M(qq) = M Z
bbšš 18% b­tagging useful
bb` + ` \Gamma (` = e=¯) 6% very clean; M(``) = M Z
qqÜ + Ü \Gamma 9% quite difficult
n.b. only bbšš and bb` + ` \Gamma usable at LEP I.
overall efficiency at LEP II ¸ 25 \Gamma 30%.
Useful at present to combine 161,172 GeV data with LEP I.
D.R. Ward PPEUC 9 April 1997

The Higgs Boson
All experiments have a few candidate events at various
(different) masses. A typical result (ALEPH) mH ? 70:7 GeV
(95% c.l.)
10
­1
1
10
45 50 55 60 65 70 75
m H (GeV/c 2 )
Expected
Signal
All data combined
N 95
LEP 1 Data
LEP 2 Data
ALEPH
70.7 GeV/c 2
Advantageous to combine data from all experiments (all­LEP
working group established). Likely to place limit at around
mH ? 75 \Gamma 77 GeV (E. Gross, Moriond).
D.R. Ward PPEUC 9 April 1997

MSSM Higgs Bosons
ffl In MSSM, two complex Higgs doublets ! five Higgs
bosons, H, h (CP even), A (CP odd) and H \Sigma .
ffl oe(Zh) = oe SM(ZH) sin 2 (fi \Gamma ff)
oe(Ah) = oe SM(ZH)– cos 2 (fi \Gamma ff)
so use the SM Higgs search (j Zh) combined with Ah
search (e.g. bbbb or bbÜ + Ü \Gamma final states.)
ffl Typical limit (ALEPH) m h ? 62:5 GeV 8 tan fi, mixing.
1
10
0 20 40 60 80 100 120 140
Excluded at 95% C.L. ALEPH
m top = 174 GeV/c 2
M SUSY = 1 TeV/c 2
Maximal mixing
m h (GeV/c 2 )
tanb
hA
hZ
D.R. Ward PPEUC 9 April 1997

The ``four­jet effect''
ffl At LEP 1.5, ALEPH saw an excess of 4­jet events. Mass
peak in \SigmaM = M ij +M kl at ¸ 106 GeV.
ffl ALEPH sees (smaller) peak at same mass at 161 and 172
GeV Other experiments see nothing
0
5
10
15
20
25
30
35
20 40 60 80 100 120 140 160 180 200
SM for minimum dM
events/4
GeV
N exp =87.6
N data =90
0
2
4
6
8
10
12
20 40 60 80 100 120 140 160 180 200
SM for minimum dM
events/4
GeV
N exp =30.3
N data =40
Observed/expected events at 130­172 GeV:
\Sigma4 GeV \Sigma6 GeV oe /pb
ALEPH 18/3.1 19/4.6 2.2\Sigma0.5
DLO 9/9.2 14/14.5 !0.5 (95% CL)
D.R. Ward PPEUC 9 April 1997

SUSY Searches at LEP II
Many other new particle searches. All have proved negative so
far. Summarize and give typical limits
(but need to read the fine print for details):
ffl Chargino/neutralino e.g. e + e \Gamma ! ~
ü + ~
ü \Gamma ; ~
ü \Sigma ! ~
ü 0 W \Sigma .
Limits are complicated (function of SUSY model
parameters), and depend on ~
ü \Sigma \Gamma ~
ü 0 mass difference.
ffl Gravitino If gravitino light -- ~
ü 0 ! ~
Gfl. From acoplanar
diphoton (ffl flflX) events e.g. M(~ü 0 ) ? 73 GeV (in
Lopez+Nanopoulos model).
ffl Squarks M( ~ t L ) ? 73 GeV (depends on L \Gamma R mixing,
\DeltaM ). Also ~ b
ffl Sleptons M(~e L ) ? 70 GeV; M(~¯L ) ? 64 GeV
ffl RPV Limits starting to emerge in R­parity violating scenarios.
D.R. Ward PPEUC 9 April 1997

MSSM Chargino/neutralino limits
\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma\Gamma
20 40 60 80 100 120 140
0
10
20
30
40
50
60
70
80
90
m(c 1
)
(GeV)
0
~
m(c 2 ) (GeV)
0
~
tan = 1.5
b
m(c 1
)
(GeV)
0
~
m(c 2 ) (GeV)
0
~
tan = 35
b
\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma
\Gamma\Gamma\Gamma
45
0
10
20
30
40
50
60
70
80
90
50 55 60 65 70 75 80 85 90
m(c 1 ) (GeV)
+
~
m(c 1
)
(GeV)
0
~
OPAL Preliminary
m(c 1 ) (GeV)
+
~
m(c 1
)
(GeV)
0
~
tan = 35
(b)
(c) (d)
b
45
0
10
20
30
40
50
60
70
80
90
50 55 60 65 70 75 80 85 90
tan = 1.5
(a)
b
20 40 60 80 100 120 140
0
10
20
30
40
50
60
70
80
90
1
E ² 161 GeV
cm
E ² 161 GeV
cm
E ² 161 GeV
cm
E ²
161 GeV
cm
Limits for light
(yellow) and
heavy (red) ~
š.
m(~ü 0 ) ? 12,
24 GeV respec­
tively.
Stop limits
Limits for
~
t 1 ! c~ü 0 .
Complementary
to D0 for small
mass differences.
M t
” and M c” 95% C.L. Exclusion
0
20
40
60
80
50 60 70 80
M t
” (GeV/c 2 )
M
c
”
(GeV/c
2
)
Q Mix = 0 o
Q Mix = 56 o
M t
” < M c”
D0 Exclusion
ALEPH Preliminary
D.R. Ward PPEUC 9 April 1997

More Searches at LEP II
ffl Heavy Neutral Leptons M(L 0 ) ? 79 GeV (Dirac)
M(L 0 ) ? 69 GeV (Majorana) if L 0 ! (e=¯)W \Lambda
72, 58 GeV respectively if L 0 ! ÜW \Lambda
ffl Heavy Charged Leptons
M(L \Sigma ) ? 80 GeV if L \Sigma ! šW \Lambda
M(L \Sigma ) ? 81 GeV if L \Sigma ! L 0 W \Lambda
M(L \Sigma ) ? 84 GeV if stable.
ffl Excited Leptons (Compositeness)
M(e \Lambda ) ? 85 GeV, M(š e \Lambda ) ? 84 GeV,
M(¯ \Lambda ) ? 85 GeV, M(š ¯ \Lambda ) ? 84 GeV,
M(Ü \Lambda ) ? 84 GeV, M(š Ü \Lambda ) ? 79 GeV.
Many of these are close to the kinematic limit for 172 GeV, even
with 10 pb \Gamma1 of data.
D.R. Ward PPEUC 9 April 1997

LEP I/SLC Electroweak Physics
A brief summary of some of the main changes since last
summer:
ffl Lineshape + A `
FB Some 1995 data added (DO) final LEP I
results await definitive beam energy.
ffl Ü polarization Nothing new
ffl R b Recent results published (AOS), lepton analysis (L)
ffl R c New vertex­based analysis (S)
ffl A b
FB New results (LO)
ffl A b , A c (L­R asymmetries) updated (S)
ffl ALR (L­R asymmetry) 1996 result available (S)
ffl QFB (charge asymmetry) new result (L)
Overall, changes quite small. Also new MW results included in
electroweak fits.
D.R. Ward PPEUC 9 April 1997

Lepton universality
­0.045
­0.040
­0.035
­0.030
­0.502 ­0.501 ­0.5
Preliminary
g Al
g
Vl
A LR (SLD)
m t
m H
l + l -
e + e -
µ + µ -
t + t -
Number of light neutrinos?
N š = 2:992 \Sigma 0:011
Additional invisible width? \Delta\Gamma inv ! 2:9 MeV (95% c.l.)
D.R. Ward PPEUC 9 April 1997

R b and R c
G b /G had
LEP+SLC 0.2177 ± 0.0011
LEP leptons 0.2217 ± 0.0023 ± 0.0020
SLD vtx mass
1993­95
0.2152 ± 0.0034 ± 0.0016
OPAL mult
1992­94
0.2178 ± 0.0014 ± 0.0017
L3 shape
1991
0.2223 ± 0.0030 ± 0.0064
L3 impact par.
1994
0.2188 ± 0.0028 ± 0.0033
DELPHI mult
1991­94
0.2205 ± 0.0014 ± 0.0018
ALEPH mult
1992­95
0.2159 ± 0.0009 ± 0.0011
0.0003 g exchange corr. added
100
150
200
250
0.21 0.22
G b /G had for G c /G had = 0.172
m t
[GeV]
G c /G had
LEP+SLD 0.1722 ± 0.0053
OPAL
charm counting 1991­93
0.167 ± 0.011 ± 0.011
DELPHI
charm counting 1991­94
0.168 ± 0.011 ± 0.013
SLD
mass+lifetime 1993­95
0.176 ± 0.016 ± 0.009
DELPHI
D * incl/incl 1991­95
0.171 ± 0.013 ± 0.015
ALEPH
D excl/excl 1991­95
0.169 ± 0.013 ± 0.011
OPAL
D * incl/excl 1991­95
0.182 ± 0.011 ± 0.014
DELPHI
D * incl/excl 1991­95
0.176 ± 0.015 ± 0.015
ALEPH
D * incl/excl 1991­95
0.176 ± 0.013 ± 0.011
DELPHI
lepton 1991­92
0.162 ± 0.009 ± 0.021
ALEPH
lepton 1990­94
0.1649 ± 0.0070 ± 0.0066
0.125 0.15 0.175 0.2
G c /G had
0.16
0.17
0.18
0.19
0.214 0.216 0.218 0.22 0.222
R b
R c
68% CL
95% CL
99% CL
SM
D.R. Ward PPEUC 9 April 1997

SM fit to LEP/SLD/pp/šp data
Measurement Pull Pull
­3 ­2 ­1 0 1 2 3
­3 ­2 ­1 0 1 2 3
m Z [GeV] 91.1863 ± 0.0019 .06
G Z [GeV] 2.4947 ± 0.0026 ­.75
s 0
hadr [nb] 41.489 ± 0.055 .46
R l 20.783 ± 0.029 .80
A fb
0,l 0.0177 ± 0.0010 1.57
A t 0.1401 ± 0.0067 ­.98
A e 0.1382 ± 0.0076 ­1.11
sin 2 q lept
eff 0.2322 ± 0.0010 .63
m W [GeV] 80.38 ± 0.14 .10
R b 0.2177 ± 0.0011 1.75
R c 0.1722 ± 0.0053 ­.01
A fb
0,b 0.0985 ± 0.0022 ­1.96
A fb
0,c 0.0735 ± 0.0048 .01
A b 0.897 ± 0.047 ­.80
A c 0.623 ± 0.085 ­.53
sin 2 q lept
eff 0.23055 ± 0.00041 ­2.48
1 ­­ m 2
W /m 2
Z 0.2244 ± 0.0042 .28
m W [GeV] 80.37 ± 0.10 .04
m t [GeV] 175.6 ± 5.5 .52
1/a 128.894 ± 0.090 ­.16
Moriond 1997
Fit SM to all data ) ü 2 /dof = 21/15.
) ff s = 0:120 \Sigma 0:003
D.R. Ward PPEUC 9 April 1997

Electroweak radiative corrections
0.2305
0.231
0.2315
0.232
0.2325
0.233
83.4 83.6 83.8 84 84.2 84.4
LEP/SLC/CDF/D0 March 1997
PRELIMINARY
a(m z )=1/128.89
a(m 2 )=1/128.89
SM m t =175.6 ± 5.5
60 Da
G lepton (MeV)
sin 2 q lept
sin 2 q eff
m t
m H
68% C.L.
95% C.L.
ffl The ? shows SM expectation with only photon vacuum
polarization corrections. ) electroweak corrections are
needed
ffl n.b. The uncertainty in ff(M Z ) is not negligible.
ffl Can use the LEP/SLD/FNAL data to constrain Higgs mass...
D.R. Ward PPEUC 9 April 1997

Implications for MH ?
140
160
180
200
10 10 2
10 3
m H [GeV]
m t
[GeV]
Excluded
Preliminary
LEP Data, G F , a
All Data
80.2
80.3
80.4
80.5
140 160 180 200
m H [GeV]
60 300 1000
m t [GeV]
m
W
[GeV]
Preliminary
indirect Data
direct Data
0
2
4
6
10 10 2
10 3
Excluded
m H [GeV]
Dc
2
Preliminary
theory uncertainty
)MH = 127 +127
\Gamma72 GeV; MH ! 465 GeV (95% c.l.)
D.R. Ward PPEUC 9 April 1997

Other LEP I/SLC Physics
A brief summary of some of the many recent results not covered
in this talk.
? 40 new papers on LEP I/SLD physics since Warsaw!
ffl b physics V cb (AO) Charm counting (A) Lifetimes (DOS)
Oscillations + CP violation (O) B! `` (L) B,D! Üš (L)
B! J=/j; J=/ú 0 (L) \Lambda b ! \Lambda` (O) B c (AD)
ffl c physics br(D 0 ! Kú) (A) D \Lambda\Lambda (O)
ffl Ü physics Ü lifetime (AL) Hadronic decay structure (AO)
CP violation (O) Ü ! j=!(783) (A) Michel parameters (S)
Ü ! ¯flšš (O)
ffl QCD Quark­gluon differences (ADO) Colour factors (A)
Scaling violations (D) Fragmentation models (AD)
j,!(783) production (L) ú 0 production (A)
Spin alignment (O) Baryon correlations (D)
Leading particle effects (S) 3­jet orientation (S)
ffl Two­photon F fl
2 (O) Longitudinal structure function (O)
Jets (O)
D.R. Ward PPEUC 9 April 1997

Summary
ffl LEP I (Z running) finished, but LEP I data far from fully
exploited
ffl SLC with polarized beams ) important complementary
results
ffl LEP II has made a successful start -- progressive energy
increases
ffl MW = 80:38 \Sigma 0:14 GeV from first 20 pb \Gamma1 of data.
ffl TGC -- no anomalies -- ff W OE ! 0:4
ffl Searches -- nothing exciting, except...
ffl four­jet effect? -- still only seen by one experiment
ffl SM Higgs -- M ? 75 GeV (LEP II)
M ! 465 GeV (electroweak radiative corrections)
ffl LEP/SLC continue to be very productive!
D.R. Ward PPEUC 9 April 1997